Portal Communications has filed a lawsuit against Apple for alleged infringement of three patents related to natural language voice query systems – the technology being used by the iPhone-maker in its products in the form of the Siri virtual assistant.

It is filing with the Eastern Texas District Court, Portal Communications said that the three related patents were invented by Dave Bernard, CEO of technology solutions firm The Intellection Group. All the patents titled “Multimodal natural language query system and architecture for processing voice and proximity-based queries” were transferred from The Intellection Group to Portal Communications in January.

Each patent deals with methods of parsing user queries from natural language patterns into machine decipherable commands, whether they be voice or text. The IP details methods of further processing requests using GPS location data, or other proximity information, to provide a context and environment for narrowing down a response.

Apple purchased Siri in 2010 when the software was available as a mobile assistant for iPhone. Initially based on Nuance voice recognition and natural language processing technology, Siri advertised its conversational attributes as one of the app’s main draws.

Apple integrated Siri into its hardware lineup with iPhone 4S in 2011, some three years after the ‘645 patent was granted. Building on Siri’s foundation, the company expanded the voice assistant’s capabilities to cover device operations and later installed the feature on other platforms including iPad, Mac, Apple Watch and, most recently, HomePod.

A complaint similar to Portal’s suit was lodged last year by Word to Info, a one-man firm that began targeting major tech companies like Amazon, Google, Microsoft and Nuance over alleged infringement of natural language processing IP. Now in its suit, Portal seeks damages for infringement with interest, a trebling of damages, court expenses and a preliminary or permanent injunction against products found to infringe on the patents-in-suit.